The lowest price component in this Rear Master Cylinder (gs750c parts-list fiche is the Nut.
Parts such as the Rear Master Cylinder (gs750c: Yoke, Nut, Bolt, Upper, Washer are included in the Gs750en 1979 (n) Usa (e03) Rear Master Cylinder (gs750c parts fiche.
In this schematic the "Nut" is used most often.